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Faustini G, Poletto F, Baston R, Tucciarone CM, Legnardi M, Dal Maso M, Genna V, Fiorentini L, Di Donato A, Perulli S, Cecchinato M, Drigo M, Franzo G. D for dominant: porcine circovirus 2d (PCV-2d) prevalence over other genotypes in wild boars and higher viral flows from domestic pigs in Italy. Front Microbiol 2024; 15:1412615. [PMID: 38952451 PMCID: PMC11215180 DOI: 10.3389/fmicb.2024.1412615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 05/20/2024] [Indexed: 07/03/2024] Open
Abstract
Introduction Porcine circovirus 2 (PCV-2) is a key pathogen for the swine industry at a global level. Nine genotypes, differing in epidemiology and potentially virulence, emerged over time, with PCV-2a, -2b, and -2d being the most widespread and clinically relevant. Conversely, the distribution of minor genotypes appears geographically and temporally restricted, suggesting lower virulence and different epidemiological drivers. In 2022, PCV-2e, the most genetically and phenotypically divergent genotype, was identified in multiple rural farms in North-eastern Italy. Since rural pigs often have access to outdoor environment, the introduction from wild boars was investigated. Methods Through a molecular and spatial approach, this study investigated the epidemiology and genetic diversity of PCV-2 in 122 wild boars across different provinces of North-eastern Italy. Results Molecular analysis revealed a high PCV-2 frequency (81.1%, 99/122), and classified the majority of strains as PCV-2d (96.3%, 78/81), with sporadic occurrences of PCV-2a (1.2%, 1/81) and PCV-2b (2.5%, 2/81) genotypes. A viral flow directed primarily from domestic pigs to wild boars was estimated by phylogenetic and phylodynamic analyses. Discussion These findings attested that the genotype replacement so far described only in the Italian domestic swine sector occurred also in wild boars. and suggested that the current heterogeneity of PCV-2d strains in Italian wild boars likely depends more on different introduction events from the domestic population rather than the presence of independent evolutionary pressures. While this might suggest PCV-2 circulation in wild boars having a marginal impact in the industrial sector, the sharing of PCV-2d strains across distinct wild populations, in absence of a consistent geographical pattern, suggests a complex interplay between domestic and wild pig populations, emphasizing the importance of improved biosecurity measures to mitigate the risk of pathogen transmission.
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Affiliation(s)
- Giulia Faustini
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Italy
| | - Francesca Poletto
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Italy
| | - Riccardo Baston
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Italy
| | | | - Matteo Legnardi
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Italy
| | - Mariangela Dal Maso
- AULSS 8 Berica, Dipartimento di Prevenzione, Servizi Veterinari, Vicenza, Italy
| | | | - Laura Fiorentini
- Istituto Zooprofilattico Sperimentale Della Lombardia E Dell'Emilia Romagna (IZSLER), Forlì, Forlì-Cesena, Italy
| | | | - Simona Perulli
- Istituto Zooprofilattico Sperimentale Della Lombardia E Dell'Emilia Romagna (IZSLER), Forlì, Forlì-Cesena, Italy
| | - Mattia Cecchinato
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Italy
| | - Michele Drigo
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Italy
| | - Giovanni Franzo
- Department of Animal Medicine, Production and Health, University of Padova, Legnaro, Italy
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Xie Y, Ahmad I, Ikpe TIS, Sofia EF, Seno H. What Influence Could the Acceptance of Visitors Cause on the Epidemic Dynamics of a Reinfectious Disease?: A Mathematical Model. Acta Biotheor 2024; 72:3. [PMID: 38402514 PMCID: PMC10894808 DOI: 10.1007/s10441-024-09478-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 01/30/2024] [Indexed: 02/26/2024]
Abstract
The globalization in business and tourism becomes crucial more and more for the economical sustainability of local communities. In the presence of an epidemic outbreak, there must be such a decision on the policy by the host community as whether to accept visitors or not, the number of acceptable visitors, or the condition for acceptable visitors. Making use of an SIRI type of mathematical model, we consider the influence of visitors on the spread of a reinfectious disease in a community, especially assuming that a certain proportion of accepted visitors are immune. The reinfectivity of disease here means that the immunity gained by either vaccination or recovery is imperfect. With the mathematical results obtained by our analysis on the model for such an epidemic dynamics of resident and visitor populations, we find that the acceptance of visitors could have a significant influence on the disease's endemicity in the community, either suppressive or supportive.
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Affiliation(s)
- Ying Xie
- Department of Mathematical and Information Sciences, Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 6-3-09, Aoba-ku, Sendai, 980-8579, Miyagi, Japan
| | - Ishfaq Ahmad
- Department of Mathematical and Information Sciences, Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 6-3-09, Aoba-ku, Sendai, 980-8579, Miyagi, Japan
| | - ThankGod I S Ikpe
- Department of Mathematical and Information Sciences, Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 6-3-09, Aoba-ku, Sendai, 980-8579, Miyagi, Japan
| | - Elza F Sofia
- Department of Mathematical and Information Sciences, Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 6-3-09, Aoba-ku, Sendai, 980-8579, Miyagi, Japan
| | - Hiromi Seno
- Department of Mathematical and Information Sciences, Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 6-3-09, Aoba-ku, Sendai, 980-8579, Miyagi, Japan.
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Rogoll L, Schulz K, Staubach C, Oļševskis E, Seržants M, Lamberga K, Conraths FJ, Sauter-Louis C. Identification of predilection sites for wild boar carcass search based on spatial analysis of Latvian ASF surveillance data. Sci Rep 2024; 14:382. [PMID: 38172492 PMCID: PMC10764341 DOI: 10.1038/s41598-023-50477-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/20/2023] [Indexed: 01/05/2024] Open
Abstract
Targeted search for wild boar carcasses is essential for successful control of African swine fever (ASF) in wild boar populations. To examine whether landscape conditions influence the probability of finding ASF-positive carcasses, this study analyzed Global Positioning System (GPS) coordinates of Latvian wild boar carcasses and hunted wild boar, extracted from the CSF/ASF wild boar surveillance database of the European Union, and random coordinates in Latvia. Geographic information system (GIS) software was used to determine the landscape type and landscape composition of carcass detection sites and to measure distances from the carcasses to nearest waterbodies, forest edges, roads and settlements. The results of the automated measurements were validated by manually analyzing a smaller sample. Wild boar carcasses were found predominantly in forested areas and closer to waterbodies and forest edges than random GPS coordinates in Latvia. Carcasses of ASF-infected wild boar were found more frequently in transitional zones between forest and woodland shrub, and at greater distances from roads and settlements compared to ASF-negative carcasses and random points. This leads to the hypothesis, that ASF-infected animals seek shelter in quiet areas further away from human disturbance. A detailed collection of information on the environment surrounding carcass detection sites is needed to characterize predilection sites more accurately.
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Affiliation(s)
- Lisa Rogoll
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany.
| | - Katja Schulz
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Christoph Staubach
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Edvīns Oļševskis
- Food and Veterinary Service, Peldu 30, Riga, 1050, Latvia
- Institute of Food Safety, Animal Health and Environment-"BIOR", Lejupes 3, Riga, 1076, Latvia
| | | | | | - Franz Josef Conraths
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
| | - Carola Sauter-Louis
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493, Greifswald-Insel Riems, Germany
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Pepin KM, Borowik T, Frant M, Plis K, Podgórski T. Risk of African swine fever virus transmission among wild boar and domestic pigs in Poland. Front Vet Sci 2023; 10:1295127. [PMID: 38026636 PMCID: PMC10657852 DOI: 10.3389/fvets.2023.1295127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction African swine fever (ASF) is a notifiable disease of swine that impacts global pork trade and food security. In several countries across the globe, the disease persists in wild boar (WB) populations sympatric to domestic pig (DP) operations, with continued detections in both sectors. While there is evidence of spillover and spillback between the sectors, the frequency of occurrence and relative importance of different risk factors for transmission at the wildlife-livestock interface remain unclear. Methods To address this gap, we leveraged ASF surveillance data from WB and DP across Eastern Poland from 2014-2019 in an analysis that quantified the relative importance of different risk factors for explaining variation in each of the ASF surveillance data from WB and DP. Results ASF prevalence exhibited different seasonal trends across the sectors: apparent prevalence was much higher in summer (84% of detections) in DP, but more consistent throughout the year in WB (highest in winter with 45%, lowest in summer at 15%). Only 21.8% of DP-positive surveillance data included surveillance in WB nearby (within 5 km of the grid cell within the last 4 weeks), while 41.9% of WB-positive surveillance samples included any DP surveillance samples nearby. Thus, the surveillance design afforded twice as much opportunity to find DP-positive samples in the recent vicinity of WB-positive samples compared to the opposite, yet the rate of positive WB samples in the recent vicinity of a positive DP sample was 48 times as likely than the rate of positive DP samples in the recent vicinity of a positive WB sample. Our machine learning analyses found that positive samples in WB were predicted by WB-related risk factors, but not to DP-related risk factors. In contrast, WB risk factors were important for predicting detections in DP on a few spatial and temporal scales of data aggregation. Discussion Our results highlight that spillover from WB to DP might be more frequent than the reverse, but that the structure of current surveillance systems challenge quantification of spillover frequency and risk factors. Our results emphasize the importance of, and provide guidance for, improving cross-sector surveillance designs.
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Affiliation(s)
- Kim M. Pepin
- National Wildlife Research Center, USDA, APHIS, Wildlife Services, Fort Collins, CO, United States
| | - Tomasz Borowik
- Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland
| | - Maciej Frant
- Department of Swine Diseases, National Veterinary Research Institute, Puławy, Poland
| | - Kamila Plis
- Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland
| | - Tomasz Podgórski
- Mammal Research Institute, Polish Academy of Sciences, Białowieża, Poland
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, Czechia
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Hayes BH, Vergne T, Andraud M, Rose N. Mathematical modeling at the livestock-wildlife interface: scoping review of drivers of disease transmission between species. Front Vet Sci 2023; 10:1225446. [PMID: 37745209 PMCID: PMC10511766 DOI: 10.3389/fvets.2023.1225446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Modeling of infectious diseases at the livestock-wildlife interface is a unique subset of mathematical modeling with many innate challenges. To ascertain the characteristics of the models used in these scenarios, a scoping review of the scientific literature was conducted. Fifty-six studies qualified for inclusion. Only 14 diseases at this interface have benefited from the utility of mathematical modeling, despite a far greater number of shared diseases. The most represented species combinations were cattle and badgers (for bovine tuberculosis, 14), and pigs and wild boar [for African (8) and classical (3) swine fever, and foot-and-mouth and disease (1)]. Assessing control strategies was the overwhelming primary research objective (27), with most studies examining control strategies applied to wildlife hosts and the effect on domestic hosts (10) or both wild and domestic hosts (5). In spatially-explicit models, while livestock species can often be represented through explicit and identifiable location data (such as farm, herd, or pasture locations), wildlife locations are often inferred using habitat suitability as a proxy. Though there are innate assumptions that may not be fully accurate when using habitat suitability to represent wildlife presence, especially for wildlife the parsimony principle plays a large role in modeling diseases at this interface, where parameters are difficult to document or require a high level of data for inference. Explaining observed transmission dynamics was another common model objective, though the relative contribution of involved species to epizootic propagation was only ascertained in a few models. More direct evidence of disease spill-over, as can be obtained through genomic approaches based on pathogen sequences, could be a useful complement to further inform such modeling. As computational and programmatic capabilities advance, the resolution of the models and data used in these models will likely be able to increase as well, with a potential goal being the linking of modern complex ecological models with the depth of dynamics responsible for pathogen transmission. Controlling diseases at this interface is a critical step toward improving both livestock and wildlife health, and mechanistic models are becoming increasingly used to explore the strategies needed to confront these diseases.
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Affiliation(s)
- Brandon H. Hayes
- IHAP, Université de Toulouse, INRAE, ENVT, Toulouse, France
- Ploufragan-Plouzané-Niort Laboratory, The French Agency for Food, Agriculture and the Environment (ANSES), Ploufragan, France
| | | | - Mathieu Andraud
- Ploufragan-Plouzané-Niort Laboratory, The French Agency for Food, Agriculture and the Environment (ANSES), Ploufragan, France
| | - Nicolas Rose
- Ploufragan-Plouzané-Niort Laboratory, The French Agency for Food, Agriculture and the Environment (ANSES), Ploufragan, France
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Sykes AL, Galvis JA, O'Hara KC, Corzo C, Machado G. Estimating the effectiveness of control actions on African swine fever transmission in commercial swine populations in the United States. Prev Vet Med 2023; 217:105962. [PMID: 37354739 DOI: 10.1016/j.prevetmed.2023.105962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/23/2023] [Accepted: 06/09/2023] [Indexed: 06/26/2023]
Abstract
Given the proximity of African swine fever (ASF) to the U.S., there is an urgent need to better understand the possible dissemination pathways of the virus within the U.S. swine industry and to evaluate mitigation strategies. Here, we extended PigSpread, a farm-level spatially-explicit stochastic compartmental transmission model incorporating six transmission routes including between-farm swine movements, vehicle movements, and local spread, to model the dissemination of ASF. We then examined the effectiveness of control actions similar to the ASF national response plan. The average number of secondary infections during the first 60 days of the outbreak was 49 finisher farms, 17 nursery farms, 5 sow farms, and less than one farm in other production types. The between-farm movements of swine were the predominant route of ASF transmission with an average contribution of 71.1%, while local spread and movement of vehicles were less critical with average contributions of 14.6% and 14.4%. We demonstrated that the combination of quarantine, depopulation, movement restrictions, contact tracing, and enhanced surveillance, was the most effective mitigation strategy, resulting in an average reduction of 79.0% of secondary cases by day 140 of the outbreak. Implementing these control actions led to a median of 495,619 depopulated animals, 357,789 diagnostic tests, and 54,522 movement permits. Our results suggest that the successful elimination of an ASF outbreak is likely to require the deployment of all control actions listed in the ASF national response plan for more than 140 days, as well as estimating the resources needed for depopulation, testing, and movement permits under these controls.
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Affiliation(s)
- Abagael L Sykes
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Jason A Galvis
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
| | - Kathleen C O'Hara
- US Department of Agriculture, Animal and Plant Health Inspection Service, Veterinary Services, Strategy and Policy, Center for Epidemiology and Animal Health, Fort Collins, CO, USA
| | - Cesar Corzo
- Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, USA
| | - Gustavo Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
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Poolkhet C, Kasemsuwan S, Thongratsakul S, Warrasuth N, Pamaranon N, Nuanualsuwan S. Prediction of the spread of African swine fever through pig and carcass movements in Thailand using a network analysis and diffusion model. PeerJ 2023; 11:e15359. [PMID: 37187529 PMCID: PMC10178211 DOI: 10.7717/peerj.15359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 04/16/2023] [Indexed: 05/17/2023] Open
Abstract
Background African swine fever (ASF) is a serious contagious viral disease of pigs that affects the pig industry. This study aimed to evaluate the possible African swine fever (ASF) distribution using network analysis and a diffusion model through live pig, carcass, and pig product movement data. Material and Methods Empirical movement data from Thailand for the year 2019 were used, and expert opinions were sought to evaluate network properties and the diffusion model. The networks were presented as live pig movement and carcass movement data at the provincial and district levels. For network analysis, a descriptive network analysis was performed using outdegree, indegree, betweenness, fragmentation, and power law distribution, and cutpoints were used to describe movement patterns. For the diffusion model, we simulated each network using spatially different infected locations, patterns, and initial infection sites. Based on expert opinions, the initial infection site, the probability of ASF occurrence, and the probability of the initial infected adopter were selected for the appropriated network. In this study, we also simulated networks under varying network parameters to predict the infection speed. Results and Conclusions The total number of movements recorded was 2,594,364. These were divided into 403,408 (403,408/2,594,364; 15.55%) for live pigs and 2,190,956 (2,190,956/2,594,364; 84.45%) for carcasses. We found that carcass movement at the provincial level showed the highest outdegree (mean = 342.554, standard deviation (SD) = 900.528) and indegree values (mean = 342.554, SD = 665.509). In addition, the outdegree and indegree presented similar mean values and the degree distributions of both district networks followed a power-law function. The network of live pigs at provincial level showed the highest value for betweenness (mean = 0.011, SD = 0.017), and the network of live pigs at provincial level showed the highest value for fragmentation (mean = 0.027, SD = 0.005). Our simulation data indicated that the disease occurred randomly due to live pig and carcass movements along the central and western regions of Thailand, causing the rapid spread of ASF. Without control measures, it could spread to all provinces within 5- and 3-time units and in all districts within 21- and 30-time units for the network of live pigs and carcasses, respectively. This study assists the authorities to plan control and preventive measures and limit economic losses caused by ASF.
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Affiliation(s)
- Chaithep Poolkhet
- Veterinary Public Health, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, Thailand
| | - Suwicha Kasemsuwan
- Veterinary Public Health, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, Thailand
| | - Sukanya Thongratsakul
- Veterinary Public Health, Kasetsart University, Kamphaeng Saen, Nakhon Pathom, Thailand
| | - Nattachai Warrasuth
- Department of Livestock Development, Ministry of Agriculture and Cooperatives, Bangkok, Thailand
| | - Nuttavadee Pamaranon
- Department of Livestock Development, Ministry of Agriculture and Cooperatives, Bangkok, Thailand
| | - Suphachai Nuanualsuwan
- Department of Veterinary Public Health, Chulalongkorn University, Bangkok, Thailand
- Center of Excellence for Food and Water Risk Analysis (FAWRA), Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
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Dankwa EA, Lambert S, Hayes S, Thompson RN, Donnelly CA. Stochastic modelling of African swine fever in wild boar and domestic pigs: Epidemic forecasting and comparison of disease management strategies. Epidemics 2022; 40:100622. [PMID: 36041286 DOI: 10.1016/j.epidem.2022.100622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 07/21/2022] [Accepted: 08/10/2022] [Indexed: 11/25/2022] Open
Abstract
African swine fever (ASF), caused by the African swine fever virus (ASFV), is highly virulent in domestic pigs and wild boar (Sus scrofa), causing up to 100% mortality. The recent epidemic of ASF in Europe has had a serious economic impact and poses a threat to global food security. Unfortunately, there is no effective treatment or vaccine against ASFV, limiting the available disease management strategies. Mathematical models allow us to further our understanding of infectious disease dynamics and evaluate the efficacy of disease management strategies. The ASF Challenge, organised by the French National Research Institute for Agriculture, Food, and the Environment, aimed to expand the development of ASF transmission models to inform policy makers in a timely manner. Here, we present the model and associated projections produced by our team during the challenge. We developed a stochastic model combining transmission between wild boar and domestic pigs, which was calibrated to synthetic data corresponding to different phases describing the epidemic progression. The model was then used to produce forward projections describing the likely temporal evolution of the epidemic under various disease management scenarios. Despite the interventions implemented, long-term projections forecasted persistence of ASFV in wild boar, and hence repeated outbreaks in domestic pigs. A key finding was that it is important to consider the timescale over which different measures are evaluated: interventions that have only limited effectiveness in the short term may yield substantial long-term benefits. Our model has several limitations, partly because it was developed in real-time. Nonetheless, it can inform understanding of the likely development of ASF epidemics and the efficacy of disease management strategies, should the virus continue its spread in Europe.
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Affiliation(s)
| | - Sébastien Lambert
- Centre for Emerging, Endemic and Exotic Diseases, Department of Pathobiology and Population Sciences, Royal Veterinary College, University of London, United Kingdom
| | - Sarah Hayes
- Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, United Kingdom
| | - Robin N Thompson
- Mathematics Institute, University of Warwick, Coventry, United Kingdom; Zeeman Institute for Systems Biology and Infectious Disease Epidemiology Research, University of Warwick, Coventry, United Kingdom
| | - Christl A Donnelly
- Department of Statistics, University of Oxford, Oxford, United Kingdom; Department of Infectious Disease Epidemiology, Faculty of Medicine, School of Public Health, Imperial College London, United Kingdom.
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Iscaro C, Cambiotti V, Bessi O, Pacelli F, Ruocco L, Feliziani F. Analysis of surveillance and prevention plan for African Swine Fever in Italy in 2020. Vet Med Sci 2022; 8:1502-1508. [PMID: 35675914 PMCID: PMC9297771 DOI: 10.1002/vms3.824] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Background African Swine Fever (ASF) is a challenge for pig health worldwide. The disease has spread to multiple countries on five continents. ASF‐free countries need to apply effective strategies to prevent the introduction of infection. Methods Italy implemented a surveillance and prevention plan for ASF in 2020, supported by a dedicated information system. Several pillars for action have been identified: passive surveillance in both domestic pigs and wild boar populations, verification of the implementation of biosecurity measures on farms and an awareness campaign for all involved stakeholders. Results There were some regional differences in the management of passive surveillance. In order to identify all critical points and apply corrective measures, regional authorities were called to carry out a gap analysis exercise in July 2020. There were an adequate number of samples collected from wild boar but the number of samples collected from domestic pigs was below the target in most regions. Furthermore, sample distribution within the country was not homogeneous. Conclusions During the forthcoming year, some issues must be addressed in order to establish an effective early detection system in Italian ASF‐free regions.
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Affiliation(s)
- Carmen Iscaro
- Istituto Zooprofilattico Sperimentale Umbria e Marche: Laboratorio Nazionale di Referenza per le Pesti Suine, Perugia, Italy
| | - Valentina Cambiotti
- Istituto Zooprofilattico Sperimentale Umbria e Marche: Sistema Informatico, Informatizzazione dei Servizi Sanitari, Perugia, Italy.,Ministero della Salute: Direzione Generale per l'Igiene e la Sicurezza degli Alimenti e la Nutrizione, ufficio VIII, Sistema di allerta, emergenze sanitarie e pianificazione dei controlli, Roma, Italy
| | - Olivia Bessi
- Ministero della Salute: Direzione Generale della Sanità Animale e dei Farmaci Veterinari, ufficio III, Sanità animale e gestione operativa del Centro nazionale di lotta ed emergenza contro le malattie animali e unità centrale di crisi, Roma, Italy
| | - Francesca Pacelli
- Ministero della Salute: Direzione Generale della Sanità Animale e dei Farmaci Veterinari, ufficio III, Sanità animale e gestione operativa del Centro nazionale di lotta ed emergenza contro le malattie animali e unità centrale di crisi, Roma, Italy
| | - Luigi Ruocco
- Ministero della Salute: Direzione Generale della Sanità Animale e dei Farmaci Veterinari, ufficio III, Sanità animale e gestione operativa del Centro nazionale di lotta ed emergenza contro le malattie animali e unità centrale di crisi, Roma, Italy
| | - Francesco Feliziani
- Istituto Zooprofilattico Sperimentale Umbria e Marche: Laboratorio Nazionale di Referenza per le Pesti Suine, Perugia, Italy
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Baños JV, Boklund A, Gogin A, Gortázar C, Guberti V, Helyes G, Kantere M, Korytarova D, Linden A, Masiulis M, Miteva A, Neghirla I, Oļševskis E, Ostojic S, Petr S, Staubach C, Thulke H, Viltrop A, Wozniakowski G, Broglia A, Abrahantes Cortiñas J, Dhollander S, Mur L, Papanikolaou A, Van der Stede Y, Zancanaro G, Ståhl K. Epidemiological analyses of African swine fever in the European Union: (September 2020 to August 2021). EFSA J 2022; 20:e07290. [PMID: 35515335 PMCID: PMC9066549 DOI: 10.2903/j.efsa.2022.7290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
This report provides a descriptive analysis of the African swine fever (ASF) Genotype II epidemic in the affected Member States in the EU and two neighbouring countries for the period from 1 September 2020 to 31 August 2021. ASF continued to spread in wild boar in the EU, it entered Germany in September 2020, while Belgium became free from ASF in October 2020. No ASF outbreaks in domestic pigs nor cases in wild boar have been reported in Greece since February 2020. In the Baltic States, overall, there has been a declining trend in proportions of polymerase chain reaction (PCR)-positive samples from wild boar carcasses in the last few years. In the other countries, the proportions of PCR-positive wild boar carcasses remained high, indicating continuing spread of the disease. A systematic literature review revealed that the risk factors most frequently significantly associated with ASF in domestic pigs were pig density, low levels of biosecurity and socio-economic factors. For wild boar, most significant risk factors were related to habitat, socio-economic factors and wild boar management. The effectiveness of different control options in the so-named white zones, areas where wild boar densities have been drastically reduced to avoid further spread of ASF after a new introduction, was assessed with a stochastic model. Important findings were that establishing a white zone is much more challenging when the area of ASF incursion is adjacent to an area where limited control measures are in place. Very stringent wild boar population reduction measures in the white zone are key to success. The white zone needs to be far enough away from the affected core area so that the population can be reduced in time before the disease arrives and the timing of this will depend on the wild boar density and the required population reduction target in the white zone. Finally, establishing a proactive white zone along the demarcation line of an affected area requires higher culling efforts, but has a higher chance of success to stop the spread of the disease than establishing reactive white zones after the disease has already entered in the area.
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11
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Fanelli A, Pellegrini F, Camero M, Catella C, Buonavoglia D, Fusco G, Martella V, Lanave G. Genetic Diversity of Porcine Circovirus Types 2 and 3 in Wild Boar in Italy. Animals (Basel) 2022; 12:953. [PMID: 35454199 PMCID: PMC9031215 DOI: 10.3390/ani12080953] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 01/27/2023] Open
Abstract
Porcine circovirus (PCV) infection is associated with relevant economic impact to the pig industry. To date, four species of PCV (PCV1 to 4) have been identified but only PCV2 has been associated firmly with disease in pigs. The objective of this study was to assess the prevalence of PCV2 and PCV3 in the wild boar population in Basilicata region, Southern Italy, since this region is characterized by large forested and rural areas and the anthropic pressure is lower than in other Italian regions. Liver samples from 82 hunted wild boar were collected in 2021 from 3 different hunting districts. Sixty (73%, 95%CI: 63-82) samples tested positive for PCVs by quantitative PCR. In detail, 22 (27%, 95%CI: 18-37) were positive for PCV2, 58 (71%, 95%CI: 60-79) for PCV3, and 20 (24.4%, 95%CI 16-35) for both PCV2 and PCV3. On genome sequencing, different types and sub-types of PCV2 and PCV3 were identified, remarking a genetic diversity and hinting to a global circulation for the identified PCV strains. Overall, the high prevalence suggests that PCV2 and PCV3 infections are endemic in the wild boar population, posing risks for semi-intensive and free-range pig farming, typical of this region, due to contact with PCV-infected wild boar.
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Affiliation(s)
- Angela Fanelli
- Department of Veterinary Medicine, University Aldo Moro of Bari, 70010 Valenzano, BA, Italy; (F.P.); (M.C.); (C.C.); (D.B.); (V.M.)
| | - Francesco Pellegrini
- Department of Veterinary Medicine, University Aldo Moro of Bari, 70010 Valenzano, BA, Italy; (F.P.); (M.C.); (C.C.); (D.B.); (V.M.)
| | - Michele Camero
- Department of Veterinary Medicine, University Aldo Moro of Bari, 70010 Valenzano, BA, Italy; (F.P.); (M.C.); (C.C.); (D.B.); (V.M.)
| | - Cristiana Catella
- Department of Veterinary Medicine, University Aldo Moro of Bari, 70010 Valenzano, BA, Italy; (F.P.); (M.C.); (C.C.); (D.B.); (V.M.)
| | - Domenico Buonavoglia
- Department of Veterinary Medicine, University Aldo Moro of Bari, 70010 Valenzano, BA, Italy; (F.P.); (M.C.); (C.C.); (D.B.); (V.M.)
| | - Giovanna Fusco
- Istituto Zooprofilattico Sperimentale del Mezzogiorno, 80055 Portici, NA, Italy;
| | - Vito Martella
- Department of Veterinary Medicine, University Aldo Moro of Bari, 70010 Valenzano, BA, Italy; (F.P.); (M.C.); (C.C.); (D.B.); (V.M.)
| | - Gianvito Lanave
- Department of Veterinary Medicine, University Aldo Moro of Bari, 70010 Valenzano, BA, Italy; (F.P.); (M.C.); (C.C.); (D.B.); (V.M.)
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12
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Key risk factors and impact of African swine fever spreading on pig production in Serbia. ACTA VET-BEOGRAD 2021. [DOI: 10.2478/acve-2021-0032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
African swine fever (ASF) is a viral disease of domestic pigs and wild boars and currently represents a major threat to the swine industry worldwide. Disease control is impaired by a lack of an effective vaccine and currently, it is dependent on biosecurity measures in pig production, rapid diagnosis, and stamping out of infected herds. Consequently, this swine disease has considerable social-economic significance on national or even regional level. In 2019 for the first time ASF was detected in the domestic swine population (backyards) in the central region of Serbia. From then on, there have been continuous outbreaks of new cases in the population of domestic and wild boars. Considering domestic pig population, in the majority of cases, ASF was detected in small holdings and backyards. The biosecurity measures are not officially required by veterinary regulation and are only given in a form of recommendations. On the other hand, it is not always possible to implement biosecurity measures that are recognized today as essential for sustainable pig production in the old type of industrial pig facilities. Nowadays, in 2021, it became obvious that the domestic pig cycle, human activities involving pigs, or pig-derived meat products are the dominant driver of virus transmission. Additionally, human activities are frequently a risky connection between domestic pigs and wild boars both directly or indirectly. Traditional, culture-related aspects and facts that politicians failed to recognise ASF as a serious issue that causes great economical losses were found to be very important obstacles in disease control.
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13
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African swine fever virus regulates host energy and amino acid metabolism to promote viral replication. J Virol 2021; 96:e0191921. [PMID: 34908441 DOI: 10.1128/jvi.01919-21] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
African swine fever is one of the most serious viral diseases caused by African swine fever virus (ASFV). The metabolic changes induced by ASFV infection remain unknown. Here, PAMs infected with ASFV was analyzed by ultra-high-performance liquid chromatography/quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS) in combination with multivariate statistical analysis. A total of 90 metabolites were significantly changed after ASFV infection, and most of them belong to amino acids and TCA cycle intermediates. ASFV infection induced increase of most of amino acids in host during the early stages of infection, and amino acids decreased in the late stages of infection. ASFV infection did not significantly affected glycolysis pathway, whereas it induced the increase of citrate, succinate, α-ketoglutarate, and oxaloacetate levels in the TCA cycle, suggesting that ASFV infection promoted TCA cycle. The activity of aspartate aminotransferase and glutamate production were significantly elevated in ASFV-infected cells and pigs, resulting in reversible transition between TCA cycle and amino acids synthesis. Aspartate, glutamate, and TCA cycle were essential for ASFV replication. In addition, ASFV infection induced an increase in lactate level using lactate dehydrogenase, which led to low expression of IFN-β and increased of ASFV replication. Our data, for the first time, indicated that ASFV infection controls IFN-β production through RIG-I-mediated signaling pathways. These data identified a novel mechanism evolved by ASFV to inhibit host innate immune responses, and will provide insights for development of new preventive or therapeutic strategies targeting the altered metabolic pathways. IMPORTANCE In order to promote viral replication, viruses often cause severe immunosuppression and seize organelles to synthesize a large number of metabolites required for self-replication. African swine fever virus (ASFV) has developed many strategies to evade host innate immune responses. However, the impact of ASFV infection on host cellular metabolism remains unknown. Here, for the first time, we analyzed the metabolomic profiles of ASFV-infected PAMs cells. ASFV infection increased host TCA cycle and amino acids metabolism. Aspartate, glutamate, and TCA cycle promoted ASFV replication. ASFV infection also induced the increase of lactate production to inhibit innate immune responses for self-replication. This study identified novel immune evasion mechanisms utilized by ASFV and provided viewpoints on ASFV-host interactions, which is critical for guiding the design of new prevention strategies against ASFV targeting the altered metabolic pathways.
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14
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Zakharova OI, Titov IA, Gogin AE, Sevskikh TA, Korennoy FI, Kolbasov DV, Abrahamyan L, Blokhin AA. African Swine Fever in the Russian Far East (2019-2020): Spatio-Temporal Analysis and Implications for Wild Ungulates. Front Vet Sci 2021; 8:723081. [PMID: 34422950 PMCID: PMC8374597 DOI: 10.3389/fvets.2021.723081] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 07/12/2021] [Indexed: 11/13/2022] Open
Abstract
African swine fever (ASF) is an emerging viral contagious disease affecting domestic pigs (DP) and wild boar (WB). ASF causes significant economic damage to the pig industry worldwide due to nearly 100% mortality and the absence of medical treatments. Since 2019, an intensive spread of ASF has been observed in the Russian Far East region. This spread raises concerns for epidemiologists and ecologists given the potential threat to the WB population, which is an essential member of the region's wild ungulates and provides a notable share of food resources for predatory species. This study aims to determine the genotype of ASF virus circulating in the region, reveal the spatio-temporal patterns of the ASF outbreaks' emergence, and assess the potential reduction of the regional fauna because of expected depopulation of WB. The first historical case of ASF in the study region was caused by an African swine fever virus (ASFV) isolated from DPs and belonging to Genotype 2, CVR1; IGR-2 (TRS +). Sequencing results showed no significant differences among ASFV strains currently circulating in the Russian Federation, Europe, and China. The spatiotemporal analysis with the space-time permutations model demonstrated the presence of six statistically significant clusters of ASF outbreaks with three clusters in DPs and one cluster in WBs. DP outbreaks prevail in the north-west regions of the study area, while northern regions demonstrate a mixture of DP and WB outbreaks. Colocation analysis did not reveal a statistically significant pattern of grouping of one category of outbreaks around the others. The possible damage to the region's fauna was assessed by modeling the total body mass of wild ungulates before and after the wild boars' depopulation, considering a threshold density of WB population of 0.025 head/km2, according to the currently in force National Plan on the ASF Eradication in Russia. The results suggest the total mass of ungulates of the entire study region will likely decrease by 8.4% (95% CI: 4.1-13.0%), while it may decrease by 33.6% (19.3-46.1%) in the Primorsky Krai, thereby posing an undeniable threat to the predatory species of the region.
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Affiliation(s)
- Olga I Zakharova
- Federal Research Center for Virology and Microbiology, Branch in Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Ilya A Titov
- Federal Research Center for Virology and Microbiology, Pokrov, Russia
| | - Andrey E Gogin
- Federal Research Center for Virology and Microbiology, Pokrov, Russia
| | | | - Fedor I Korennoy
- Federal Research Center for Virology and Microbiology, Branch in Nizhny Novgorod, Nizhny Novgorod, Russia.,Federal Center for Animal Health (FGBI ARRIAH), Vladimir, Russia
| | - Denis V Kolbasov
- Federal Research Center for Virology and Microbiology, Pokrov, Russia
| | - Levon Abrahamyan
- Swine and Poultry Infectious Diseases Research Center (CRIPA) and Groupe de Recherche sur les Maladies Infectieuses en Production Animale (GREMIP), Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, QC, Canada
| | - Andrey A Blokhin
- Federal Research Center for Virology and Microbiology, Branch in Nizhny Novgorod, Nizhny Novgorod, Russia
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15
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Clemmons EA, Alfson KJ, Dutton JW. Transboundary Animal Diseases, an Overview of 17 Diseases with Potential for Global Spread and Serious Consequences. Animals (Basel) 2021; 11:2039. [PMID: 34359167 PMCID: PMC8300273 DOI: 10.3390/ani11072039] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/24/2021] [Accepted: 06/25/2021] [Indexed: 12/21/2022] Open
Abstract
Animals provide food and other critical resources to most of the global population. As such, diseases of animals can cause dire consequences, especially disease with high rates of morbidity or mortality. Transboundary animal diseases (TADs) are highly contagious or transmissible, epidemic diseases, with the potential to spread rapidly across the globe and the potential to cause substantial socioeconomic and public health consequences. Transboundary animal diseases can threaten the global food supply, reduce the availability of non-food animal products, or cause the loss of human productivity or life. Further, TADs result in socioeconomic consequences from costs of control or preventative measures, and from trade restrictions. A greater understanding of the transmission, spread, and pathogenesis of these diseases is required. Further work is also needed to improve the efficacy and cost of both diagnostics and vaccines. This review aims to give a broad overview of 17 TADs, providing researchers and veterinarians with a current, succinct resource of salient details regarding these significant diseases. For each disease, we provide a synopsis of the disease and its status, species and geographic areas affected, a summary of in vitro or in vivo research models, and when available, information regarding prevention or treatment.
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Affiliation(s)
- Elizabeth A. Clemmons
- Southwest National Primate Research Center, Texas Biomedical Research Institute, 8715 W. Military Drive, San Antonio, TX 78227, USA;
| | - Kendra J. Alfson
- Texas Biomedical Research Institute, 8715 W. Military Drive, San Antonio, TX 78227, USA
| | - John W. Dutton
- Southwest National Primate Research Center, Texas Biomedical Research Institute, 8715 W. Military Drive, San Antonio, TX 78227, USA;
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16
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Nielsen SS, Alvarez J, Bicout DJ, Calistri P, Canali E, Drewe JA, Garin‐Bastuji B, Gonzales Rojas JL, Herskin M, Miranda Chueca MÁ, Michel V, Padalino B, Pasquali P, Roberts HC, Sihvonen LH, Spoolder H, Stahl K, Velarde A, Viltrop A, Winckler C, Blome S, More S, Gervelmeyer A, Antoniou S, Gortázar Schmidt C. African swine fever and outdoor farming of pigs. EFSA J 2021; 19:e06639. [PMID: 34140998 PMCID: PMC8188572 DOI: 10.2903/j.efsa.2021.6639] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
This opinion describes outdoor farming of pigs in the EU, assesses the risk of African swine fewer (ASF) introduction and spread associated with outdoor pig farms and proposes biosecurity and control measures for outdoor pig farms in ASF-affected areas of the EU. Evidence was collected from Member States (MSs) veterinary authorities, farmers' associations, literature and legislative documents. An Expert knowledge elicitation (EKE) was carried out to group outdoor pig farms according to their risk of introduction and spread of ASF, to rank biosecurity measures regarding their effectiveness with regard to ASF and propose improvements of biosecurity for outdoor pig farming and accompanying control measures. Outdoor pig farming is common and various farm types are present throughout the EU. As there is no legislation at European level for categorising outdoor pig farms in the EU, information is limited, not harmonised and needs to be interpreted with care. The baseline risk of outdoor pig farms for ASFV introduction and its spread is high but with considerable uncertainty. The Panel is 66-90% certain that, if single solid or double fences were fully and properly implemented on all outdoor pig farms in areas of the EU where ASF is present in wild boar and in domestic pigs in indoor farms and outdoor farms (worst case scenario not considering different restriction zones or particular situations), without requiring any other outdoor-specific biosecurity measures or control measures, this would reduce the number of new ASF outbreaks occurring in these farms within a year by more than 50% compared to the baseline risk. The Panel concludes that the regular implementation of independent and objective on-farm biosecurity assessments using comprehensive standard protocols and approving outdoor pig farms on the basis of their biosecurity risk in an official system managed by competent authorities will further reduce the risk of ASF introduction and spread related to outdoor pig farms.
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17
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Hayes BH, Andraud M, Salazar LG, Rose N, Vergne T. Mechanistic modelling of African swine fever: A systematic review. Prev Vet Med 2021; 191:105358. [PMID: 33930624 DOI: 10.1016/j.prevetmed.2021.105358] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 04/06/2021] [Accepted: 04/13/2021] [Indexed: 12/11/2022]
Abstract
The spread of African swine fever (ASF) poses a grave threat to the global swine industry. Without an available vaccine, understanding transmission dynamics is essential for designing effective prevention, surveillance, and intervention strategies. These dynamics can often be unraveled through mechanistic modelling. To examine the assumptions on transmission and objectives of the mechanistic models of ASF, a systematic review of the scientific literature was conducted. Articles were examined across multiple epidemiological and model characteristics, with filiation between models determined through the creation of a neighbor-joined tree using phylogenetic software. Thirty-four articles qualified for inclusion, with four main modelling objectives identified: estimating transmission parameters (11 studies), assessing determinants of transmission (7), examining consequences of hypothetical outbreaks (5), assessing alternative control strategies (11). Population-based (17), metapopulation (5), and individual-based (12) model frameworks were represented, with population-based and metapopulation models predominantly used among domestic pigs, and individual-based models predominantly represented among wild boar. The majority of models (25) were parameterized to the genotype II isolates currently circulating in Europe and Asia. Estimated transmission parameters varied widely among ASFV strains, locations, and transmission scale. Similarly, parameter assumptions between models varied extensively. Uncertainties on epidemiological and ecological parameters were usually accounted for to assess the impact of parameter values on the modelled infection trajectory. To date, almost all models are host specific, being developed for either domestic pigs or wild boar despite the fact that spillover events between domestic pigs and wild boar are evidenced to play an important role in ASF outbreaks. Consequently, the development of more models incorporating such transmission routes is crucial. A variety of codified and hypothetical control strategies were compared however they were all a priori defined interventions. Future models, built to identify the optimal contributions across many control methods for achieving specific outcomes should provide more useful information for policy-makers. Further, control strategies were examined in competition with each other, which is opposed to how they would actually be synergistically implemented. While comparing strategies is beneficial for identifying a rank-order efficacy of control methods, this structure does not necessarily determine the most effective combination of all available strategies. In order for ASFV models to effectively support decision-making in controlling ASFV globally, these modelling limitations need to be addressed.
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Affiliation(s)
- Brandon H Hayes
- UMR ENVT-INRAE IHAP, National Veterinary School of Toulouse, 31000, Toulouse, France; Epidemiology Health and Welfare Department, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 22440, Ploufragan, France.
| | - Mathieu Andraud
- Epidemiology Health and Welfare Department, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 22440, Ploufragan, France
| | - Luis G Salazar
- Epidemiology Health and Welfare Department, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 22440, Ploufragan, France
| | - Nicolas Rose
- Epidemiology Health and Welfare Department, Ploufragan-Plouzané-Niort Laboratory, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 22440, Ploufragan, France
| | - Timothée Vergne
- UMR ENVT-INRAE IHAP, National Veterinary School of Toulouse, 31000, Toulouse, France
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18
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Brookes VJ, Barrett TE, Ward MP, Roby JA, Hernandez-Jover M, Cross EM, Donnelly CM, Barnes TS, Wilson CS, Khalfan S. A scoping review of African swine fever virus spread between domestic and free-living pigs. Transbound Emerg Dis 2021; 68:2643-2656. [PMID: 33455062 DOI: 10.1111/tbed.13993] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Revised: 01/12/2021] [Accepted: 01/13/2021] [Indexed: 12/31/2022]
Abstract
Since 2007, African swine fever virus (ASFV) has spread to countries in Europe, Asia and Oceania and has caused devastating impacts on pigs and the pork industry. Transmission can be direct or indirect, and epidemiologic scenarios have been described in which spread occurs between free-living and domestic pigs. The purpose of this scoping review was to identify primary research in which authors made statements to support ASFV transmission between free-living and domestic pigs and assess the circumstances in which transmission events occurred. A search was conducted in five bibliographic databases and the grey literature. Two reviewers (from a team of ten) independently screened each record and charted data (demographics of the pig populations, their husbandry [domestic pigs] and habitat [free-living pigs], the spatial and temporal distribution of ASF, the occurrence or burden of ASF in the populations, and whether ticks were present in the geographic range of the pig populations). Data synthesis included statistics and a narrative summary. From 1,349 records screened, data were charted from 46 individual studies published from 1985 to 2020. Outbreak investigations revealed that whilst poor biosecurity of domestic pig operations was often reported, direct contact resulting in transmission between free-living and domestic pigs was rarely reported. Studies in which quantitative associations were made generally found that spread within populations was more important than spread between populations, although this was not always the case, particularly when domestic pigs were free-ranging. We conclude that there is limited evidence that transmission of ASFV between free-living and domestic pigs is an important feature of ASF epidemiology, especially in the current ASF epidemic in Europe and the Russian Federation. If ASFV elimination cannot be achieved in free-living pigs, compartmentalization of domestic pig populations from free-living populations via biosecurity strategies could be used to support trade of domestic pigs.
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Affiliation(s)
- Victoria J Brookes
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Tamille E Barrett
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Michael P Ward
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW, Australia
| | - Justin A Roby
- Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia.,School of Biomedical Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Marta Hernandez-Jover
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Emily M Cross
- School of Biomedical Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Camilla M Donnelly
- School of Biomedical Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Tamsin S Barnes
- The University of Queensland, School of Veterinary Science, Gatton, Qld, Australia.,The University of Queensland, Queensland Alliance for Agriculture and Food Innovation, Gatton, Qld, Australia
| | - Cara S Wilson
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
| | - Shahid Khalfan
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation (NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga, NSW, Australia
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19
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Kirkeby C, Brookes VJ, Ward MP, Dürr S, Halasa T. A Practical Introduction to Mechanistic Modeling of Disease Transmission in Veterinary Science. Front Vet Sci 2021; 7:546651. [PMID: 33575275 PMCID: PMC7870987 DOI: 10.3389/fvets.2020.546651] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 12/21/2020] [Indexed: 11/13/2022] Open
Abstract
Computer-based disease spread models are frequently used in veterinary science to simulate disease spread. They are used to predict the impacts of the disease, plan and assess surveillance, or control strategies, and provide insights about disease causation by comparing model outputs with real life data. There are many types of disease spread models, and here we present and describe the implementation of a particular type: individual-based models. Our aim is to provide a practical introduction to building individual-based disease spread models. We also introduce code examples with the goal to make these techniques more accessible to those who are new to the field. We describe the important steps in building such models before, during and after the programming stage, including model verification (to ensure that the model does what was intended), validation (to investigate whether the model results reflect the modeled system), and convergence analysis (to ensure models of endemic diseases are stable before outputs are collected). We also describe how sensitivity analysis can be used to assess the potential impact of uncertainty about model parameters. Finally, we provide an overview of some interesting recent developments in the field of disease spread models.
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Affiliation(s)
- Carsten Kirkeby
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark,*Correspondence: Carsten Kirkeby
| | - Victoria J. Brookes
- School of Animal and Veterinary Sciences, Faculty of Science, Charles Sturt University, Wagga, NSW, Australia,Graham Centre for Agricultural Innovation (Charles Sturt University and NSW Department of Primary Industries), Wagga, NSW, Australia
| | - Michael P. Ward
- Faculty of Veterinary Science, Sydney School of Veterinary Science, University of Sydney, Sydney, NSW, Australia
| | - Salome Dürr
- Department of Clinical Research and Public Health, Veterinary Public Health Institute, University of Bern, Bern, Switzerland
| | - Tariq Halasa
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg, Denmark
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20
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Galvis JA, Jones CM, Prada JM, Corzo CA, Machado G. The between-farm transmission dynamics of porcine epidemic diarrhoea virus: A short-term forecast modelling comparison and the effectiveness of control strategies. Transbound Emerg Dis 2021; 69:396-412. [PMID: 33475245 DOI: 10.1111/tbed.13997] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/11/2021] [Accepted: 01/18/2021] [Indexed: 01/10/2023]
Abstract
A limited understanding of the transmission dynamics of swine disease is a significant obstacle to prevent and control disease spread. Therefore, understanding between-farm transmission dynamics is crucial to developing disease forecasting systems to predict outbreaks that would allow the swine industry to tailor control strategies. Our objective was to forecast weekly porcine epidemic diarrhoea virus (PEDV) outbreaks by generating maps to identify current and future PEDV high-risk areas, and simulating the impact of control measures. Three epidemiological transmission models were developed and compared: a novel epidemiological modelling framework was developed specifically to model disease spread in swine populations, PigSpread, and two models built on previously developed ecosystems, SimInf (a stochastic disease spread simulations) and PoPS (Pest or Pathogen Spread). The models were calibrated on true weekly PEDV outbreaks from three spatially related swine production companies. Prediction accuracy across models was compared using the receiver operating characteristic area under the curve (AUC). Model outputs had a general agreement with observed outbreaks throughout the study period. PoPS had an AUC of 0.80, followed by PigSpread with 0.71, and SimInf had the lowest at 0.59. Our analysis estimates that the combined strategies of herd closure, controlled exposure of gilts to live viruses (feedback) and on-farm biosecurity reinforcement reduced the number of outbreaks. On average, 76% to 89% reduction was seen in sow farms, while in gilt development units (GDU) was between 33% to 61% when deployed to sow and GDU farms located in probabilistic high-risk areas. Our multi-model forecasting approach can be used to prioritize surveillance and intervention strategies for PEDV and other diseases potentially leading to more resilient and healthier pig production systems.
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Affiliation(s)
- Jason A Galvis
- Department of Population Health and Pathobiology, College of Veterinary Medicine, Raleigh, NC, USA
| | - Chris M Jones
- Center for Geospatial Analytics, North Carolina State University, Raleigh, NC, USA
| | - Joaquin M Prada
- School of Veterinary Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
| | - Cesar A Corzo
- Veterinary Population Medicine Department, College of Veterinary Medicine, University of Minnesota, St Paul, MN, USA
| | - Gustavo Machado
- Department of Population Health and Pathobiology, College of Veterinary Medicine, Raleigh, NC, USA.,Center for Geospatial Analytics, North Carolina State University, Raleigh, NC, USA
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Andraud M, Rose N. Modelling infectious viral diseases in swine populations: a state of the art. Porcine Health Manag 2020; 6:22. [PMID: 32843990 PMCID: PMC7439688 DOI: 10.1186/s40813-020-00160-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 06/25/2020] [Indexed: 02/06/2023] Open
Abstract
Mathematical modelling is nowadays a pivotal tool for infectious diseases studies, completing regular biological investigations. The rapid growth of computer technology allowed for development of computational tools to address biological issues that could not be unravelled in the past. The global understanding of viral disease dynamics requires to account for all interactions at all levels, from within-host to between-herd, to have all the keys for development of control measures. A literature review was performed to disentangle modelling frameworks according to their major objectives and methodologies. One hundred and seventeen articles published between 1994 and 2020 were found to meet our inclusion criteria, which were defined to target papers representative of studies dealing with models of viral infection dynamics in pigs. A first descriptive analysis, using bibliometric indexes, permitted to identify keywords strongly related to the study scopes. Modelling studies were focused on particular infectious agents, with a shared objective: to better understand the viral dynamics for appropriate control measure adaptation. In a second step, selected papers were analysed to disentangle the modelling structures according to the objectives of the studies. The system representation was highly dependent on the nature of the pathogens. Enzootic viruses, such as swine influenza or porcine reproductive and respiratory syndrome, were generally investigated at the herd scale to analyse the impact of husbandry practices and prophylactic measures on infection dynamics. Epizootic agents (classical swine fever, foot-and-mouth disease or African swine fever viruses) were mostly studied using spatio-temporal simulation tools, to investigate the efficiency of surveillance and control protocols, which are predetermined for regulated diseases. A huge effort was made on model parameterization through the development of specific studies and methodologies insuring the robustness of parameter values to feed simulation tools. Integrative modelling frameworks, from within-host to spatio-temporal models, is clearly on the way. This would allow to capture the complexity of individual biological variabilities and to assess their consequences on the whole system at the population level. This would offer the opportunity to test and evaluate in silico the efficiency of possible control measures targeting specific epidemiological units, from hosts to herds, either individually or through their contact networks. Such decision support tools represent a strength for stakeholders to help mitigating infectious diseases dynamics and limiting economic consequences.
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Affiliation(s)
- M. Andraud
- Anses, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare research unit, F22440 Ploufragan, France
| | - N. Rose
- Anses, French Agency for Food, Environmental and Occupational Health & Safety, Ploufragan-Plouzané-Niort Laboratory, Epidemiology, Health and Welfare research unit, F22440 Ploufragan, France
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22
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Epidemiological analysis of the 2015–2017 African swine fever outbreaks in Estonia. Prev Vet Med 2020; 181:104556. [DOI: 10.1016/j.prevetmed.2018.10.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/01/2018] [Indexed: 11/21/2022]
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23
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Danzetta ML, Marenzoni ML, Iannetti S, Tizzani P, Calistri P, Feliziani F. African Swine Fever: Lessons to Learn From Past Eradication Experiences. A Systematic Review. Front Vet Sci 2020; 7:296. [PMID: 32582778 PMCID: PMC7296109 DOI: 10.3389/fvets.2020.00296] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/30/2020] [Indexed: 11/13/2022] Open
Abstract
Prevention, early detection, prompt reaction, and communication play a crucial role in African swine fever (ASF) control. Appropriate surveillance capable of early detection of the disease in both domestic and wild animals, and the implementation of consolidated contingency plans, are currently considered the best means of controlling this disease. The purpose of this study was to understand the lessons to be learned through the global disease eradication history. To establish which strategies were successful for prevention, control, and eradication of ASF, and which errors should not be repeated, we conducted a systematic review. A query was defined to search for surveillance and control strategies applied by countries worldwide for ASF eradication in the past. Inclusion and exclusion criteria were defined. Decisions on study eligibility and data extraction were performed by two independent reviewers and the differences were resolved by consensus or by a third reviewer. From 1,980 papers, 23 were selected and included in the qualitative analysis. Reports from Belgium, Brazil, Cuba, the Dominican Republic and Haiti, France, mainland Italy, Malta, Portugal, and Spain were included. Despite the economic resources allocated and the efforts made, eradication was possible in only eight countries, between the 50s and 90s in the twentieth century, in different epidemiological and cultural contexts, in some instances within <1 year, and in others in about 40 years. Classical surveillance strategies, such as active and passive surveillance, both at farm and slaughterhouse levels, targeted surveillance, together with conventional biosafety and sanitary measures, led to eradication even in countries in which the tick's epidemiological role was demonstrated. Historical surveillance data analysis indicated that eradication was possible even when technological tools either were not available or were used less than they are currently. This emphasizes that data on surveillance and on animal population are crucial for planning effective surveillance, and targeting proper control and intervention strategies. This paper demonstrates that some strategies applied in the past were effective; these could be implemented and improved to confront the current epidemiological wave. This offers encouragement for the efforts made particularly in Europe during the recent epidemics.
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Affiliation(s)
- Maria Luisa Danzetta
- National Reference Centre for Veterinary Epidemiology and Risk Analysis (COVEPI), Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, G. Caporale, Teramo, Italy
- Department of Veterinary Medicine, University of Perugia, Perugia, Italy
| | | | - Simona Iannetti
- National Reference Centre for Veterinary Epidemiology and Risk Analysis (COVEPI), Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, G. Caporale, Teramo, Italy
| | - Paolo Tizzani
- World Animal Health Information and Analysis Department (WAHIAD), World Organisation for Animal Health, OIE, Paris, France
| | - Paolo Calistri
- National Reference Centre for Veterinary Epidemiology and Risk Analysis (COVEPI), Istituto Zooprofilattico Sperimentale dell'Abruzzo e del Molise, G. Caporale, Teramo, Italy
| | - Francesco Feliziani
- National Reference Laboratory for Swine Fevers, Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche “Togo Rosati”, Perugia, Italy
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24
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Spatio-Temporal Analysis of the Spread of ASF in the Russian Federation in 2017-2019. ACTA VET-BEOGRAD 2020. [DOI: 10.2478/acve-2020-0014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Currently, African swine fever (ASF) is one of the biggest global economic challenges in Europe and Asia. Despite all the efforts done to understand the mechanism of spread, presence and maintenance of ASF in domestic pigs and wild boar, there are still many gaps in the knowledge on its epidemiology.
This study aims to describe spatial and temporal patterns of ASF spread in wild boar and domestic pigs in the country during the last three years. Methods of Spatio-temporal scanning statistics of Kulldorff (SatScan) and Mann-Kendell statistics (space-time cube) were used to identify potential clusters of outbreaks and the presence of hot spots (areas of active flare clusters), respectively. The results showed that ASF in the country has a local epidemic pattern of spread (11 explicit clusters in wild boar and 16 epizootic clusters were detected in the domestic pig population: 11 in the European part and 5 in the Asian part), and only six of them are overlapped suggesting that ASF epidemics in domestic pigs and wild boar are two separate processes. In the Nizhny Novgorod, Vladimir, Ivanovo, Novgorod, Pskov, Leningrad regions, the clusters identified are characterized as sporadic epidemics clusters, while in the Ulyanovsk region, Primorsky Territory, and the Jewish Autonomous Region the clusters are consistent. Considering the low biosecurity level of pig holdings in the far east and its close economic and cultural connections with China as well as other potential risk factors, it can be expected that the epidemic will be present in the region for a long time. The disease has spread in the country since 2007, and now it is reoccurring in some of the previously affected regions. Outbreaks in the domestic pig sector can be localized easily (no pattern detected), while the presence of the virus in wildlife (several consecutive hot spots detected) hampers its complete eradication. Although the disease has different patterns of spread over the country its driving forces remain the same (human-mediated spread and wild boar domestic-pigs mutual spillover). The results indicate that despite all efforts taken since 2007, the policy of eradication of the disease needs to be reviewed, especially measures in wildlife.
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Bosch J, Barasona JA, Cadenas-Fernández E, Jurado C, Pintore A, Denurra D, Cherchi M, Vicente J, Sánchez-Vizcaíno JM. Retrospective spatial analysis for African swine fever in endemic areas to assess interactions between susceptible host populations. PLoS One 2020; 15:e0233473. [PMID: 32469923 PMCID: PMC7259610 DOI: 10.1371/journal.pone.0233473] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/05/2020] [Indexed: 12/21/2022] Open
Abstract
African Swine Fever (ASF) is one of the most complex and significant diseases from a sanitary-economic perspective currently affecting the world's swine-farming industry. ASF has been endemic in Sardinia (Italy) since 1978, and several control and eradication programmes have met with limited success. In this traditional ASF endemic area, there are three susceptible host populations for this virus sharing the same habitat: wild boar, farmed domestic pigs and non-registered free-ranging pigs (known as "brado" animals). The main goal of this study was to determine and predict fine-scale spatial interactions of this multi-host system in relation to the epidemiology of ASF in the main endemic area of Sardinia, Montes-Orgosolo. To this end, simultaneous monitoring of GPS-GSM collared wild boar and free-ranging pigs sightings were performed to predict interaction indexes through latent selection difference functions with environmental, human and farming factors. Regarding epidemiological assessment, the spatial inter-specific interaction indexes obtained here were used to correlate ASF notifications in wild boar and domestic pig farms. Daily movement patterns, home ranges (between 120.7 and 2,622.8 ha) and resource selection of wild boar were obtained for the first time on the island. Overall, our prediction model showed the highest spatial interactions between wild boar and free-ranging pigs in areas close to pig farms. A spatially explicit model was obtained to map inter-specific interaction over the complete ASF-endemic area of the island. Our approach to monitoring interaction indexes may help explain the occurrence of ASF notifications in wild boar and domestic pigs on a fine-spatial scale. These results support the recent and effective eradication measures taken in Sardinia. In addition, this methodology could be extrapolated to apply in the current epidemiological scenarios of ASF in Eurasia, where exist multi-host systems involving free-ranging pigs and wild boar.
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Affiliation(s)
- Jaime Bosch
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Jose A. Barasona
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Estefanía Cadenas-Fernández
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Cristina Jurado
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Antonio Pintore
- Istituto Zooprofilattico Sperimentale della Sardegna, Sardinia, Italy
| | - Daniele Denurra
- Istituto Zooprofilattico Sperimentale della Sardegna, Sardinia, Italy
| | - Marcella Cherchi
- Istituto Zooprofilattico Sperimentale della Sardegna, Sardinia, Italy
| | - Joaquín Vicente
- Spanish Wildlife Research Institute (IREC) (CSIC-UCLM), Ciudad Real, Spain
| | - Jose M. Sánchez-Vizcaíno
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
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26
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O'Neill X, White A, Ruiz-Fons F, Gortázar C. Modelling the transmission and persistence of African swine fever in wild boar in contrasting European scenarios. Sci Rep 2020; 10:5895. [PMID: 32246098 PMCID: PMC7125206 DOI: 10.1038/s41598-020-62736-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 03/13/2020] [Indexed: 11/09/2022] Open
Abstract
African swine fever (ASF) is a severe viral disease that is currently spreading among domestic pigs and wild boar (Sus scrofa) in large areas of Eurasia. Wild boar play a key role in the spread of ASF, yet despite their significance, little is known about the key mechanisms that drive infection transmission and disease persistence. A mathematical model of the wild boar ASF system is developed that captures the observed drop in population density, the peak in infected density and the persistence of the virus observed in ASF outbreaks. The model results provide insight into the key processes that drive the ASF dynamics and show that environmental transmission is a key mechanism determining the severity of an infectious outbreak and that direct frequency dependent transmission and transmission from individuals that survive initial ASF infection but eventually succumb to the disease are key for the long-term persistence of the virus. By considering scenarios representative of Estonia and Spain we show that faster degradation of carcasses in Spain, due to elevated temperature and abundant obligate scavengers, may reduce the severity of the infectious outbreak. Our results also suggest that the higher underlying host density and longer breeding season associated with supplementary feeding leads to a more pronounced epidemic outbreak and persistence of the disease in the long-term. The model is used to assess disease control measures and suggests that a combination of culling and infected carcass removal is the most effective method to eradicate the virus without also eradicating the host population, and that early implementation of these control measures will reduce infection levels whilst maintaining a higher host population density and in some situations prevent ASF from establishing in a population.
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Affiliation(s)
- Xander O'Neill
- Maxwell Institute for Mathematical Sciences, Department of Mathematics, Heriot-Watt University, Edinburgh, EH14 4AS, UK
| | - Andy White
- Maxwell Institute for Mathematical Sciences, Department of Mathematics, Heriot-Watt University, Edinburgh, EH14 4AS, UK.
| | - Francisco Ruiz-Fons
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM & CSIC), 13005, Ciudad Real, Spain
| | - Christian Gortázar
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM & CSIC), 13005, Ciudad Real, Spain
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27
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Cadenas-Fernández E, Sánchez-Vizcaíno JM, Pintore A, Denurra D, Cherchi M, Jurado C, Vicente J, Barasona JA. Free-Ranging Pig and Wild Boar Interactions in an Endemic Area of African Swine Fever. Front Vet Sci 2019; 6:376. [PMID: 31737649 PMCID: PMC6831522 DOI: 10.3389/fvets.2019.00376] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 10/11/2019] [Indexed: 12/05/2022] Open
Abstract
African swine fever virus (ASFV) is spreading throughout Eurasia and there is no vaccine nor treatment available, so the control is based on the implementation of strict sanitary measures. These measures include depopulation of infected and in-contact animals and export restrictions, which can lead to important economic losses, making currently African swine fever (ASF) the greatest threat to the global swine industry. ASF has been endemic on the island of Sardinia since 1978, the longest persistence of anywhere in Eurasia. In Sardinia, eradication programs have failed, in large part due to the lack of farm professionalism, the high density of wild boar and the presence of non-registered domestic pigs (free-ranging pigs). In order to clarify how the virus is transmitted from domestic to wild swine, we examined the interaction between free-ranging pigs and wild boar in an ASF-endemic area of Sardinia. To this end, a field study was carried out on direct and indirect interactions, using monitoring by camera trapping in different areas and risk points. Critical time windows (CTWs) for the virus to survive in the environment (long window) and remain infectious (short window) were estimated, and based on these, the number of indirect interactions were determined. Free-ranging pigs indirectly interacted often with wild boar (long window = 6.47 interactions/day, short window = 1.31 interactions/day) and these interactions (long window) were mainly at water sources. They also directly interacted 0.37 times per day, especially between 14:00 and 21:00 h, which is much higher than for other interspecific interactions observed in Mediterranean scenarios. The highly frequent interactions at this interspecific interface may help explain the more than four-decade-long endemicity of ASF on the island. Supporting that free-ranging pigs can act as a bridge to transmit ASFV between wild boar and registered domestic pigs. This study contributes broadly to improving the knowledge on the estimation of frequencies of direct and indirect interactions between wild and free-ranging domestic swine. As well as supporting the importance of the analysis of interspecific interactions in shared infectious diseases, especially for guiding disease management. Finally, this work illustrates the power of the camera-trapping method for analyzing interspecific interfaces.
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Affiliation(s)
- Estefanía Cadenas-Fernández
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Jose M Sánchez-Vizcaíno
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Antonio Pintore
- Istituto Zooprofilattico Sperimentale della Sardegna, Sardinia, Italy
| | - Daniele Denurra
- Istituto Zooprofilattico Sperimentale della Sardegna, Sardinia, Italy
| | - Marcella Cherchi
- Istituto Zooprofilattico Sperimentale della Sardegna, Sardinia, Italy
| | - Cristina Jurado
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
| | - Joaquín Vicente
- Spanish Wildlife Research Institute (IREC) (CSIC-UCLM), Ciudad Real, Spain
| | - Jose A Barasona
- VISAVET Health Surveillance Centre, Animal Health Department, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain
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28
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Schulz K, Conraths FJ, Blome S, Staubach C, Sauter-Louis C. African Swine Fever: Fast and Furious or Slow and Steady? Viruses 2019; 11:E866. [PMID: 31533266 PMCID: PMC6783890 DOI: 10.3390/v11090866] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/13/2019] [Accepted: 09/14/2019] [Indexed: 11/16/2022] Open
Abstract
Since the introduction of African swine fever (ASF) into Georgia in 2007, the disease has been spreading in an unprecedented way. Many countries that are still free from the disease fear the emergence of ASF in their territory either in domestic pigs or in wild boar. In the past, ASF was often described as being a highly contagious disease with mortality often up to 100%. However, the belief that the disease might enter a naïve population and rapidly affect the entire susceptible population needs to be critically reviewed. The current ASF epidemic in wild boar, but also the course of ASF within outbreaks in domestic pig holdings, suggest a constant, but relatively slow spread. Moreover, the results of several experimental and field studies support the impression that the spread of ASF is not always fast. ASF spread and its speed depend on various factors concerning the host, the virus, and also the environment. Many of these factors and their effects are not fully understood. For this review, we collated published information regarding the spreading speed of ASF and the factors that are deemed to influence the speed of ASF spread and tried to clarify some issues and open questions in this respect.
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Affiliation(s)
- Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Franz Josef Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Sandra Blome
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany.
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29
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Loi F, Cappai S, Coccollone A, Rolesu S. Standardized Risk Analysis Approach Aimed to Evaluate the Last African Swine Fever Eradication Program Performance, in Sardinia. Front Vet Sci 2019; 6:299. [PMID: 31572734 PMCID: PMC6753231 DOI: 10.3389/fvets.2019.00299] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 08/23/2019] [Indexed: 11/13/2022] Open
Abstract
From more than 40 years African swine fever (ASF) is endemic in Sardinia. Historically, areas at higher risk are located throughout some inland parts of this island where domestic pigs are still illegally kept in semi-wild conditions, living in contact with the local wild boar population, thereby creating perfect conditions for disease endemicity. A new eradication plan (EP-ASF15-18) has been ongoing for the past 3 years, based on a comprehensive strategy adapted to the local situation and focused on strong actions on domestic pig farms, wild boars (WB), and the third Sardinian typical involved population [illegal free-ranging pigs (FRPs)]. A fundamental aspect of the plan is the classification of pig farms as "controlled" or "certified," based on clinical, structural, and biosecurity characteristics. The eradication plan also provides for strong action against illegal farms and pig meat marketing channels. In addition, this plan establishes specific control measures for WB hunting and ASF checks. Each control strategy is specifically based on municipality risk level, to focus actions and resources on areas at higher risk of endemic or re-emerging ASF. Thus, precise risk classification is fundamental to this goal. The aim of the present work was to establish an ASF risk index, to provide a summary measure of the risk level in the Sardinian municipalities. This synthetic measure can express the different aspects of a multidimensional phenomenon with a single numerical value, facilitating territorial and temporal comparisons. To this end, retrospective data (years 2011-2018) were used. The ASF risk index is the result of the algorithmic combination of numerical elementary indicators: disease prevalence in the suid populations, WB compliance with EP-ASF15-18, domestic pig compliance with EP-ASF15-18, and presence of FRPs. A negative binomial regression model has been applied and predictors calculated to obtain a risk index for each municipality. The result of the risk analysis was discussed and considered according to expert opinion and consensus. The results of this study, expressed as risk score and classified into five risk levels, can be used to help define actions to be carried out in each Sardinian municipality, according to the risk assessment for the territory.
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Affiliation(s)
- Federica Loi
- Istituto Zooprofilattico Sperimentale della Sardegna - Osservatorio Epidemiologico Veterinario regionale, Cagliari, Italy
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Dansu EJ, Seno H. A model for epidemic dynamics in a community with visitor subpopulation. J Theor Biol 2019; 478:115-127. [PMID: 31228488 PMCID: PMC7094103 DOI: 10.1016/j.jtbi.2019.06.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 06/16/2019] [Accepted: 06/19/2019] [Indexed: 11/04/2022]
Abstract
With a model consisting of SIR and SIS models, we affirm claims in previous works. We derive different basic reproduction numbers looking at varying perspectives. We discuss the biological meanings of these basic reproduction numbers. All the basic reproduction numbers coincide with respect to the critical condition. Relevant public health policies are proposed based on our findings.
With a five dimensional system of ordinary differential equations based on the SIR and SIS models, we consider the dynamics of epidemics in a community which consists of residents and short-stay visitors. Taking different viewpoints to consider public health policies to control the disease, we derive different basic reproduction numbers and clarify their common/different mathematical natures so as to understand their meanings in the dynamics of the epidemic. From our analyses, the short-stay visitor subpopulation could become significant in determining the fate of diseases in the community. Furthermore, our arguments demonstrate that it is necessary to choose one variant of basic reproduction number in order to formulate appropriate public health policies.
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Affiliation(s)
- Emmanuel J Dansu
- Research Center for Pure and Applied Mathematics, Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 6-3-09, Aoba-ku, Sendai 980-8579, Japan.
| | - Hiromi Seno
- Research Center for Pure and Applied Mathematics, Graduate School of Information Sciences, Tohoku University, Aramaki-Aza-Aoba 6-3-09, Aoba-ku, Sendai 980-8579, Japan
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31
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Schulz K, Staubach C, Blome S, Viltrop A, Nurmoja I, Conraths FJ, Sauter-Louis C. Analysis of Estonian surveillance in wild boar suggests a decline in the incidence of African swine fever. Sci Rep 2019; 9:8490. [PMID: 31186505 PMCID: PMC6560063 DOI: 10.1038/s41598-019-44890-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 05/21/2019] [Indexed: 12/02/2022] Open
Abstract
African swine fever (ASF) in wild boar populations is difficult to control. In affected areas, samples from all wild boar shot and found dead are investigated. The use of laboratory tests allows estimating the duration of the infection in affected animals. The study aimed to test the hypothesis that the stage of the epidemic in different areas of Estonia can be assessed on the basis of prevalence estimates. ASF surveillance data of Estonian wild boar were used to estimate prevalences and compare them between the East and West of Estonia. The temporal trend of the estimated prevalence of ASF virus positive animals and of the estimated seroprevalence of wild boar showing antibodies against ASFV was analyzed. Due to the potential influence of population density on the course of ASF in wild boar, also population density data (number of wild boar/km2) were used to investigate the relationship with laboratory test results. In areas, where the epidemic had already lasted for a long time, a small number of new cases emerged recently. The prevalence of samples that were only seropositive was significantly higher in these regions as compared to areas, where the epidemic is in full progress. The observed course of the disease could be the beginning of an ASF endemicity in this region. However, the results may also indicate that ASF has started to subside in the areas that were first affected in Estonia.
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Affiliation(s)
- Katja Schulz
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald, Insel Riems, Germany.
| | - Christoph Staubach
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Sandra Blome
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Diagnostic Virology, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Arvo Viltrop
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014, Tartu, Estonia
| | - Imbi Nurmoja
- Estonian University of Life Science, Institute of Veterinary Medicine and Animal Sciences, Kreutzwaldi 62, 51014, Tartu, Estonia
- Estonian Veterinary and Food Laboratory (VFL), Kreutzwaldi 30, 51006, Tartu, Estonia
| | - Franz Josef Conraths
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Carola Sauter-Louis
- Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Epidemiology, Südufer 10, 17493, Greifswald, Insel Riems, Germany
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Loi F, Laddomada A, Coccollone A, Marrocu E, Piseddu T, Masala G, Bandino E, Cappai S, Rolesu S. Socio-economic factors as indicators for various animal diseases in Sardinia. PLoS One 2019; 14:e0217367. [PMID: 31158242 PMCID: PMC6546212 DOI: 10.1371/journal.pone.0217367] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 05/10/2019] [Indexed: 11/19/2022] Open
Abstract
The need to consider the role of social factors in the efficacy of farm management and, consequently, in the onset and persistence of diseases typical to animal farms is increasingly being realized increasingly worldwide. Many risk analysis studies have been conducted to assess the role of various factors in the development of animal diseases; however, very few have accounted for the role of social factors. The aim of this work was to bridge this gap, with the main hypothesis that different socio-economic factors could be valid indicators for the occurrence of different animal diseases. A socio-economic analysis was performed using demographic characteristics of the farmers and data from 44 social indicators released by the Italian Statistician National Institute of Statistics (ISTAT) database. African swine fever (ASF) in wild boars (WB) and domestic pigs and other endemic animal diseases and zoonoses in Sardinia were considered, such as cistic echinococcosis (CE), contagious agalactia (CA), trichinellosis, West Nile disease (WND), and bluetongue (BT). Seven different negative binomial regression models were fitted using the number of cases between 2011-2017. Three indicators-cultural demand, employment rate, and legality-showed a statistically significant association with risk for all the diseases considered, but with varying effects. Some indicators, such as the age and sex of the farmer, material deprivation index, number of farms and animals, micro-criminality index, and rate of reported thefts were common to ASF, CA, trichinellosis, and CE cases. Others such as the forest surface and the energy produced from renewable sources were common to BT, WND, and ASF in WB. Tourism in seasons other than summer was a valid predictor of ASF and trichinellosis, while out-of-region hospital use had a statistically significant role in CE risk identification. These results may help understand the social context in which these diseases may occur and thus guide the design and implementation of additional risk management measures that go beyond well-known veterinary measures.
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Affiliation(s)
- Federica Loi
- OEVR—Osservatorio Epidemiologico Veterinario Regionale della Sardegna, Cagliari, Italy
- * E-mail:
| | - Alberto Laddomada
- Istituto Zooprofilattico Sperimentale della Sardegna “G. Pegreffi”, Sassari, Italy
| | - Annamaria Coccollone
- OEVR—Osservatorio Epidemiologico Veterinario Regionale della Sardegna, Cagliari, Italy
| | - Elena Marrocu
- OEVR—Osservatorio Epidemiologico Veterinario Regionale della Sardegna, Cagliari, Italy
| | - Toni Piseddu
- CeNRE—Centro Nazionale di Referenza per l’Echinococcosi/Idatidosi, Sassari, Italy
| | - Giovanna Masala
- CeNRE—Centro Nazionale di Referenza per l’Echinococcosi/Idatidosi, Sassari, Italy
| | - Ennio Bandino
- Istituto Zooprofilattico Sperimentale della Sardegna “G. Pegreffi”, Sassari, Italy
| | - Stefano Cappai
- OEVR—Osservatorio Epidemiologico Veterinario Regionale della Sardegna, Cagliari, Italy
| | - Sandro Rolesu
- OEVR—Osservatorio Epidemiologico Veterinario Regionale della Sardegna, Cagliari, Italy
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Laddomada A, Rolesu S, Loi F, Cappai S, Oggiano A, Madrau MP, Sanna ML, Pilo G, Bandino E, Brundu D, Cherchi S, Masala S, Marongiu D, Bitti G, Desini P, Floris V, Mundula L, Carboni G, Pittau M, Feliziani F, Sanchez-Vizcaino JM, Jurado C, Guberti V, Chessa M, Muzzeddu M, Sardo D, Borrello S, Mulas D, Salis G, Zinzula P, Piredda S, De Martini A, Sgarangella F. Surveillance and control of African Swine Fever in free-ranging pigs in Sardinia. Transbound Emerg Dis 2019; 66:1114-1119. [PMID: 30715791 PMCID: PMC6849606 DOI: 10.1111/tbed.13138] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 01/28/2019] [Accepted: 01/28/2019] [Indexed: 12/25/2022]
Abstract
African swine fever (ASF) is a notifiable infectious disease, caused by the ASF virus (ASFV), which is a DNA virus belonging to the family Asfarviridae, genus Asfivirus. This disease has gained importance in the last decade after its spread in several countries in Eastern and Central Europe, and more recently, in China. Despite the efforts made to eradicate it, ASF is still present on the Mediterranean island of Sardinia (Italy) and has been since 1978. ASF risk factors on the island have been analysed in previous studies; the role of free-ranging pigs in virus persistence has been suggested, but has not been fully elucidated. The most recent eradication plan provides more stringent measures to combat free-ranging pigs and any kind of illegality in the pig sector. From December 2017 to June 2018, a total of 29 depopulation actions were performed in 13 municipalities in central Sardinia, during which 2,281 free-ranging pigs were culled and more than 50% of them were tested for ASFV and antibody presence (1,218 and 1,416, respectively). A total of 651 pigs were seropositive, with a mean seroprevalence of 53.4% (CI 95% = 50.6-56.3), and 38 were ASFV positive (virus prevalence = 2.6%; CI 95% = 2.1-3.0). To the best of our knowledge, the present study is the first to provide a complete evaluation of this millennial system of pig farming and ASFV prevalence in free-ranging pigs. Furthermore, it has emphasised the necessity of combining the maintenance of an epidemiological surveillance program with continuous education of farmers and other people involved in pig husbandry, based on cultural and economic aspects.
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Affiliation(s)
- Alberto Laddomada
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Sandro Rolesu
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy.,Osservatorio Epidemiologico Veterinario Regionale, Cagliari, Italy
| | - Federica Loi
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy.,Osservatorio Epidemiologico Veterinario Regionale, Cagliari, Italy
| | - Stefano Cappai
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy.,Osservatorio Epidemiologico Veterinario Regionale, Cagliari, Italy
| | - Annalisa Oggiano
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Maria Paola Madrau
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Maria Luisa Sanna
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Giovannantonio Pilo
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Ennio Bandino
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Diego Brundu
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Simonetta Cherchi
- Istituto Zooprofilattico Sperimentale della Sardegna "G. Pegreffi", Sassari, Italy
| | - Sergio Masala
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
| | - Daniela Marongiu
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
| | - Giuseppe Bitti
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
| | - Pietro Desini
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
| | - Vincenzo Floris
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
| | - Luigi Mundula
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
| | - Giovanni Carboni
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
| | - Marco Pittau
- Università degli Studi, Dipartimento di Medicina Veterinaria, Sassari, Italy
| | - Francesco Feliziani
- Istituto Zooprofilattico Sperimentale dell'Umbria e delle Marche, Perugia, Italy
| | - José Manuel Sanchez-Vizcaino
- VISAVET Health Surveillance Centre and Animal Health Department, Veterinary School, Complutense University of Madrid, Madrid, Spain
| | - Cristina Jurado
- VISAVET Health Surveillance Centre and Animal Health Department, Veterinary School, Complutense University of Madrid, Madrid, Spain
| | - Vittorio Guberti
- Istituto Superiore per la Protezione e la Ricerca Ambientale, Bologna, Italy
| | | | | | | | | | - Daniela Mulas
- Regione Autonoma della Sardegna, Assessorato dell'Igiene e sanità e dell'assistenza sociale, Cagliari, Italy
| | - Gianni Salis
- Regione Autonoma della Sardegna, Assessorato dell'Igiene e sanità e dell'assistenza sociale, Cagliari, Italy
| | - Paola Zinzula
- Regione Autonoma della Sardegna, Assessorato dell'Igiene e sanità e dell'assistenza sociale, Cagliari, Italy
| | - Sebastiano Piredda
- Regione Autonoma della Sardegna, Assessorato dell'Igiene e sanità e dell'assistenza sociale, Cagliari, Italy
| | - Alessandro De Martini
- Regione Autonoma della Sardegna, Assessorato dell'Igiene e sanità e dell'assistenza sociale, Cagliari, Italy
| | - Francesco Sgarangella
- Servizio di Sanità Animale, Azienda Tutela della Salute della Sardegna, Sassari, Italy
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34
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Fekede RJ, van Gils H, Huang L, Wang X. High probability areas for ASF infection in China along the Russian and Korean borders. Transbound Emerg Dis 2019; 66:852-864. [PMID: 30520567 DOI: 10.1111/tbed.13094] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 10/18/2018] [Accepted: 11/24/2018] [Indexed: 11/27/2022]
Abstract
African swine fever (ASF) is a transcontinental, contagious, fatal virus disease of pig with devastating socioeconomic impacts. Interaction between infected wild boar and domestic pig may spread the virus. The disease is spreading fast from the west of Eurasia towards ASF-free China. Consequently, prediction of the distribution of ASF along the Sino-Russian-Korean borders is urgent. Our area of interest is Northeast China. The reported ASF-locations in 11 contiguous countries from the Baltic to the Russian Federation were extracted from the archive of the World Organization for Animal Health from July 19, 2007 to March 27, 2017. The locational records of the wild boar were obtained from literature. The environmental predictor variables were downloaded from the WorldClim website. Spatial rarefication and pair-wise geographic distance comparison were applied to minimize spatial autocorrelation of presence points. Principal component analysis (PCA) was used to minimize multi-collinearity among predictor variables. We selected the maximum entropy algorithm for spatial modelling of ASF and wild boar separately, combined the wild boar prediction with the domestic pig census in a single map of suids and overlaid the ASF with the suids map. The accuracy of the models was assessed by the AUC. PCA delivered five components accounting for 95.7% of the variance. Spatial autocorrelation was shown to be insignificant for both ASF and wild boar records. The spatial models showed high mean AUC (0.92 and 0.97) combined with low standard deviations (0.003 and 0.006) for ASF and wild boar, respectively. The overlay of the ASF and suids maps suggests that a relatively short sector of the Sino-Russian border has a high probability entry point of ASF at current conditions. Two sectors of the Sino-Korean border present an elevated risk.
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Affiliation(s)
- Regassa Joka Fekede
- Center of Conservation Medicine & Ecological Safety, Northeast Forestry University, Harbin, Heilongjiang province, China.,College of Wildlife Resource, Northeast Forestry University, Harbin, Heilongjiang province, China
| | - Hein van Gils
- Center of Conservation Medicine & Ecological Safety, Northeast Forestry University, Harbin, Heilongjiang province, China.,Department of Geography, Geoinformatics & Meteorology, University of Pretoria, Pretoria, Gauteng Province, South Africa
| | - LiYa Huang
- Changbai Mountain Academy of Sciences, Antu, Jilin province, China
| | - XiaoLong Wang
- Center of Conservation Medicine & Ecological Safety, Northeast Forestry University, Harbin, Heilongjiang province, China.,College of Wildlife Resource, Northeast Forestry University, Harbin, Heilongjiang province, China
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35
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Jurado C, Martínez-Avilés M, De La Torre A, Štukelj M, de Carvalho Ferreira HC, Cerioli M, Sánchez-Vizcaíno JM, Bellini S. Relevant Measures to Prevent the Spread of African Swine Fever in the European Union Domestic Pig Sector. Front Vet Sci 2018; 5:77. [PMID: 29713637 PMCID: PMC5912175 DOI: 10.3389/fvets.2018.00077] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/26/2018] [Indexed: 12/30/2022] Open
Abstract
During the past decade, African swine fever (ASF) has spread from the Caucasus region to eastern European Union countries affecting domestic pig and wild boar populations. In order to avert ASF spread, mitigation measures targeting both populations have been established. However, despite these efforts, ASF has been reported in thirteen different countries (Georgia, Azerbaijan, Armenia, the Russian Federation, Ukraine, Belarus, Estonia, Latvia, Lithuania, Poland, Moldova, Czech Republic, and Romania). In the absence of an effective vaccine or treatment to ASF, introduction and spread of ASF onto domestic pig farms can only be prevented by strict compliance to control measures. This study systematically reviewed available measures to prevent the spread of ASF in the EU domestic pig sector distinguishing between commercial, non-commercial, and outdoor farms. The search was performed in PubMed and using a common browser. A total of 52 documents were selected for the final review process, which included scientific articles, reports, EU documents and official recommendations, among others. From this literature review, 37 measures were identified as preventive measures for the introduction and spread of ASF. Subsequently, these measures were assessed by ASF experts for their relevance in the mitigation of ASF spread on the three mentioned types of farms. All experts agreed that some of the important preventive measures for all three types of farms were: the identification of animals and farm records; strict enforcement of the ban on swill feeding; and containment of pigs, so as to not allow direct or indirect pig–pig and/or pig–wild boar contacts. Other important preventive measures for all farms were education of farmers, workers, and operators; no contact between farmers and farm staff and external pigs; appropriate removal of carcasses, slaughter residues, and food waste; proper disposal of manure and dead animals, and abstaining from hunting activities during the previous 48 h (allowing a 48 h interval between hunting and being in contact with domestic pigs). Finally, all experts identified that the important preventive measures for non-commercial and outdoor farms is to improve access of those farms to veterinarians and health services.
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Affiliation(s)
- Cristina Jurado
- VISAVET Health Surveillance Centre, Animal Health Department, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
| | - Marta Martínez-Avilés
- Animal Health Research Centre, National Institute for Agricultural and Food Research and Technology (INIA-CISA), Madrid, Spain
| | - Ana De La Torre
- Animal Health Research Centre, National Institute for Agricultural and Food Research and Technology (INIA-CISA), Madrid, Spain
| | - Marina Štukelj
- Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
| | | | - Monica Cerioli
- Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna (IZSLER), Brescia, Italy
| | - José Manuel Sánchez-Vizcaíno
- VISAVET Health Surveillance Centre, Animal Health Department, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
| | - Silvia Bellini
- Istituto Zooprofilattico Sperimentale della Lombardia ed Emilia Romagna (IZSLER), Brescia, Italy
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Guinat C, Porphyre T, Gogin A, Dixon L, Pfeiffer DU, Gubbins S. Inferring within-herd transmission parameters for African swine fever virus using mortality data from outbreaks in the Russian Federation. Transbound Emerg Dis 2018; 65:e264-e271. [PMID: 29120101 PMCID: PMC5887875 DOI: 10.1111/tbed.12748] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Indexed: 11/28/2022]
Abstract
Mortality data are routinely collected for many livestock and poultry species, and they are often used for epidemiological purposes, including estimating transmission parameters. In this study, we infer transmission rates for African swine fever virus (ASFV), an important transboundary disease of swine, using mortality data collected from nine pig herds in the Russian Federation with confirmed outbreaks of ASFV. Parameters in a stochastic model for the transmission of ASFV within a herd were estimated using approximate Bayesian computation. Estimates for the basic reproduction number varied amongst herds, ranging from 4.4 to 17.3. This was primarily a consequence of differences in transmission rate (range: 0.7-2.2), but also differences in the mean infectious period (range: 4.5-8.3 days). We also found differences amongst herds in the mean latent period (range: 5.8-9.7 days). Furthermore, our results suggest that ASFV could be circulating in a herd for several weeks before a substantial increase in mortality is observed in a herd, limiting the usefulness of mortality data as a means of early detection of an outbreak. However, our results also show that mortality data are a potential source of data from which to infer transmission parameters, at least for diseases which cause high mortality.
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Affiliation(s)
- C Guinat
- Veterinary Epidemiology, Economics and Public Health Group, Royal Veterinary College, Hatfield, Hertfordshire, UK.,The Pirbright Institute, Pirbright, Surrey, UK
| | - T Porphyre
- The Roslin Institute, University of Edinburgh, Roslin, Midlothian, UK
| | - A Gogin
- European Food Safety Authority, Parma, Italy.,Federal Research Center for Virology and Microbiology, Pokrov, Russia
| | - L Dixon
- The Pirbright Institute, Pirbright, Surrey, UK
| | - D U Pfeiffer
- Veterinary Epidemiology, Economics and Public Health Group, Royal Veterinary College, Hatfield, Hertfordshire, UK.,College of Veterinary Medicine & Life Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - S Gubbins
- The Pirbright Institute, Pirbright, Surrey, UK
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37
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Charrier F, Rossi S, Jori F, Maestrini O, Richomme C, Casabianca F, Ducrot C, Jouve J, Pavio N, Le Potier MF. Aujeszky's Disease and Hepatitis E Viruses Transmission between Domestic Pigs and Wild Boars in Corsica: Evaluating the Importance of Wild/Domestic Interactions and the Efficacy of Management Measures. Front Vet Sci 2018; 5:1. [PMID: 29417054 PMCID: PMC5787731 DOI: 10.3389/fvets.2018.00001] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 01/03/2018] [Indexed: 11/13/2022] Open
Abstract
Wildlife species as reservoirs of infectious pathogens represent a serious constraint in the implementation of disease management strategies. In the Mediterranean island of Corsica, the dynamics of hepatitis E virus (HEV) and Aujeszky’s disease virus (ADV) are suspected to be influenced by interactions between wild and domestic pigs. To improve our understanding of these influences, we first compared the seroprevalences of both viruses in domestic pig populations from different locations with contrasted levels of wild–domestic interactions, ADV vaccination, biosafety, and farm husbandry. Second, we performed an analysis at a more restricted geographical scale, to assess the matching of ADV or HEV prevalence between sympatric wild boar and outdoor pig farms most exposed to interactions with wildlife. Logistic models were adjusted to the observed data. A high seroprevalence of HEV (>80%) and ADV (40%) in pigs, with no significant difference according to the region, confirms that both pathogens are enzootic in Corsica. Vaccination against ADV had a strong protective effect, even when performed voluntarily by farmers. Farm biosafety had an additional effect on pigs’ exposure, suggesting that contact between wild boars and pigs were involved in disease transmission. A strong correlation in HEV seroprevalence was observed between pigs and wild boars that were in close contact, and significantly lower seroprevalence was observed in pigs when they had little contact with wild boars due to spatial segregation. These results suggest a regular HEV circulation between sympatric wild boar and domestic pigs. The high HEV seroprevalence observed in domestic pigs (>80%) suggests a spillover of the virus from domestic to wild populations through environmental contamination, but this hypothesis has to be confirmed. Conversely, even though avoiding sows’ release on pasture during estrus showed some protecting effect in the free ranging pig farms regarding ADV, ADV seroprevalence was not dependent on the swine populations (wild or domestic) or on the wild–domestic spatial overlap, suggesting two quasi-separate enzootic cycles. This information will prove useful for designing more efficient disease management strategies in Corsica and similar contexts.
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Affiliation(s)
- François Charrier
- Laboratoire de Recherche sur le Développement de l'élevage (LRDE), INRA, Corte, France.,Laboratoire Interdisciplinaire, Sciences, Innovations, Sociétés, INRA, Marne-la-Vallée, France
| | - Sophie Rossi
- Unité sanitaire de la Faune, Office National de la Chasse et de la Faune Sauvage, Gap, France
| | - Ferran Jori
- CIRAD, UMR ASTRE (Animal, Santé, Territoires, Risque et Environnement), Montpellier, France.,ASTRE, University of Montpellier, CIRAD, INRA, Montpellier, France
| | - Oscar Maestrini
- Laboratoire de Recherche sur le Développement de l'élevage (LRDE), INRA, Corte, France
| | - Céline Richomme
- Laboratoire de la rage et de la faune sauvage, ANSES, Nancy, France
| | - François Casabianca
- Laboratoire de Recherche sur le Développement de l'élevage (LRDE), INRA, Corte, France
| | - Christian Ducrot
- UR346 EpiA, Centre de recherche Auvergne Rhône Alpes, INRA, Saint Genes-Champanelle, France
| | - Johan Jouve
- UMR Lieux, Identités, Espaces et Activités (LISA), CNRS-Université Pascal Paoli, Corte, France
| | - Nicole Pavio
- UMR 1161 Virology, Animal Health Laboratory, ANSES-INRA-ENVA, Maisons-Alfort, France
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38
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Jori F, Relun A, Trabucco B, Charrier F, Maestrini O, Chavernac D, Cornelis D, Casabianca F, Etter EMC. Questionnaire-Based Assessment of Wild Boar/Domestic Pig Interactions and Implications for Disease Risk Management in Corsica. Front Vet Sci 2017; 4:198. [PMID: 29250528 PMCID: PMC5716975 DOI: 10.3389/fvets.2017.00198] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/03/2017] [Indexed: 11/13/2022] Open
Abstract
Wild boars and domestic pigs belong to the same species (Sus scrofa). When sympatric populations of wild boars, feral pigs, and domestic pigs share the same environment, interactions between domestic and wild suids (IDWS) are suspected to facilitate the spread and maintenance of several pig pathogens which can impact on public health and pig production. However, information on the nature and factors facilitating those IDWS are rarely described in the literature. In order to understand the occurrence, nature, and the factors facilitating IDWS, a total of 85 semi-structured interviews were implemented face to face among 25 strict farmers, 20 strict hunters, and 40 hunting farmers in the main traditional pig-farming regions of Corsica, where IDWS are suspected to be common and widespread. Different forms of IDWS were described: those linked with sexual attraction of wild boars by domestic sows (including sexual interactions and fights between wild and domestic boars) were most frequently reported (by 61 and 44% of the respondents, respectively) in the autumn months and early winter. Foraging around common food or water was equally frequent (reported by 60% of the respondents) but spread all along the year except in winter. Spatially, IDWS were more frequent in higher altitude pastures were pig herds remain unattended during summer and autumn months with limited human presence. Abandonment of carcasses and carcass offal in the forest were equally frequent and efficient form of IDWS reported by 70% of the respondents. Certain traditional practices already implemented by hunters and farmers had the potential to mitigate IDWS in the local context. This study provided quantitative evidence of the nature of different IDWS in the context of extensive commercial outdoor pig farming in Corsica and identified their spatial and temporal trends. The identification of those trends is useful to target suitable times and locations to develop further ecological investigations of IDWS at a finer scale in order to better understand diseases transmission patterns between populations and promote adapted management strategies.
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Affiliation(s)
- Ferran Jori
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
| | - Anne Relun
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France.,BIOEPAR, ONIRIS, INRA, Nantes, France
| | - Bastien Trabucco
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,INRA, Laboratoire de Recherches sur le Développement de l'Elevage (LRDE), Corte, France
| | - François Charrier
- INRA, Laboratoire de Recherches sur le Développement de l'Elevage (LRDE), Corte, France
| | - Oscar Maestrini
- INRA, Laboratoire de Recherches sur le Développement de l'Elevage (LRDE), Corte, France
| | - David Chavernac
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
| | - Daniel Cornelis
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France
| | - François Casabianca
- INRA, Laboratoire de Recherches sur le Développement de l'Elevage (LRDE), Corte, France
| | - Eric Marcel Charles Etter
- CIRAD, UMR Animal, Santé, Territoires, Risque et Ecosystèmes (ASTRE), Montpellier, France.,ASTRE, Univ Montpellier, CIRAD, INRA, Montpellier, France.,Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Pretoria, South Africa
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